Soluble oil and transparent emulsion



Patented Juiy M, 3942 want SOLUBLE OIL AND TRANSPARENT EMULSION William E. Bradley, Los Angeles, Calii'., assignor to Union Oil Company of California, Los Angeles Calih, a corporation or California No Drawing. Application April 1, 1939,

Serial No. 265,585

18 Claims.

This invention relates to the so-called soluble or emulsifiable oils, which are products capable of ready dispersion in water to form emulsions. The object of the invention is to produce stable transparent emulsions which may be used for the various purposes to which the soluble and emulsiflable oils are put, for example, as cutting oils inthe metal industries and as carriers for dyes and the like as in the use of diluted dyecontaining emulsions for dyeing oranges. Primarily, the invention resides in compositions comprising mineral oils such as light lubricating oils, alkali metalsoaps of naphthenic acids, and relatively small proportions of at least two common solvents of different characteristics, wherein the percentage of soap of any given molecular weight is proportioned with respect to the oil and the common solvents to produce soluble oils which will be transparent when dispersed in water. In general, two types of common solvents are employed. One type is primarily watersoluble and is represented by the high boiling glycols of which ethylene glycol and diethylene glycol are preferred; such a glycol is necessary to insure the indicated transparency. The other type of necessary common solvent is primarily "oil-soluble and is represented by'pine oil, alpha terpineol, high boiling oil-soluble aliphatic alcohols like octyl alcohol, and an oil-soluble subgroup such as rosin or other abietic acid material and cresylic acid, which sub-group has the additional function of reducing the amount of naphthenate which is necessary to insure said transparency. The invention also resides in such compositions wherein the soaps vary from about 10% to 12% when obtained from naphthenic acids derived from heavy lubricating oil up to about 65% where the soaps are obtained from the naphthenic acids from gas oil, the mineral oil content ranging between about 20% and about 70% or 80%. The invention resides also in such compositions wherein the common solvents are employed in the order of about (or perhaps 3% to 7%) of each of two or more of the solvents used. The invention also includes the use in such compositions of rosin or other abietic acid material or cresylic acid to reduce the optimum or minimum soap content required for the production of transparent emulsions. This aspect may include the use of such abietic acid material or cresylic acid as a third common solvent or as the only common solvent of said second type. The optimum amount of such abietic acid material or cresylic acid appears to be between 4% and 5% of the composition, or in other words about 5%.

' ents.

jI'hus 5% rosin will decrease the optimum soap content of light lubricating oil naphthenates from about 35% without the rosin to about 23% optimum with the rosin.

In practicing the invention the soap employed is sodium or potassium naphthenate, preferably potassium naphthenate. Where sodium naphthenate is used, a slightly greater proportion is required. The naphthenic acids used in making thesoaps may be recovered from various petroleum fractions, for example, from heavy gas oils or light lubricating oils or heavy lubricating oils. The more viscous the oil the greater the molecular weight of the acid recovered and of the resultant soap, and the heavier the soap the smaller is the quantity required for producing the transparent emulsion. The recovery of naphthenic acids is well understood. They are obtained from waste alkali washes in petroleum refining wherein they are contained as partly saponlfied productsl They are recovered in various ways such as described in Robber 1,582,227 and Frizell Naphthenic acids are believed to be carboxylic acid derivatives containing naphthene or polynaphthene rings and are known to be naturally present in many petroleum distillates. When the said distillates are contacted with alkali, the resultant water-soluble naphthenates pass into the aqueous phase and can be recovered therefrom by treatment of the waste alkali with a mineral acid of the type of sulfuric acid.

Normally naphthenic acids arerecovered as soaps in the presence of a considerable proportion of mineral oil which is unavoidably carried along in the operation, and the heavier the soap or acid, the greater the oil content ordinarily. For that reason the amount-of lubricating oil to be added to the mix is less than the total required in the product. Also, as much as several percent of water accompanies the soap unless specially dehydrated. The alkali metal soaps are watersoluble and tend to produce oil-in-water emulsions and therefore are preferable to metal soaps of the type of aluminum naphthenate which are not water-soluble and tend to produce water-inoil emulsions. v

Having obtained the required alkali mctal naphthenate, with the indicated incidental oil and water content, the following general procedure is employed in compounding soluble oils of the present invention, regardless of the speciflc percentage content of the various constitu- A neutral naphthenic acid soap, such as potassium naphthenate, is first mixed with the is then cooled somewhat."

- ,thendrawnand packaged.

desired percentage of rosin, where rosin is to be temperature until all of the rosin is thoroughly incorporated in the soap-oil mixture. The batch For example, if the temperature of around 200" Fpis employed when various common solvents as indicated inthe folincorporating rosin, the rosin mixture will be I brought down to perhaps 140 F. to 160" F. If no rosin is employed, thesoap and oil areblended at'suitable temperatures, e.. g. 200 F., and then cooled to even lowertemperatures such as 100" F.

for example 5% each ofalpha tcrpineol and diethylene glycoL: and, whererosinis absent, an

. to: 150 F, To the cooled mixture the, required I amounts of other common solvents are added,

additional 5% of cresylicacidif desired. These materials are thoroughly blended at approxithe final mineral oil contentwill also be added.

At this stage the mixture maybe tested to insure that it produces a transparent emulsion, the

- percentage contentsof soap and possible com nion solvent being increased if adequate transparency-has not been obtained, The

The resultant soluble oils from the above compounding procedure are capable of various degrees .of dilution. Forexample, one part of compounded oil may bediluted with nine parts: of

.- m'ately the indicated temperatures until a' ho mogeneous mixture is obtained. During this stage any mineral oil that is required to attain lowing table will necessarily vary from a. freely liquid condition at normal'temperatures to viscous compositions atnormal temperatures according to the amount of soap and common sol vent employed.

As will. be noted lromthe lollowing table, a common solvent from group I, that is a glycol, is always employed; and usually in percentages approximating 5%, which however'can be as low as 3% or even 2% and obviously'may run somewhat higher, for examplefi' a or 8% without how ever, producing appreciable apparent benefits.

Also a common solvent from group II (oil-soluble and water-soluble) is always employed, especially where it is desired to increase liquidity and good transparency in the resultant emulsions; Where rosin or cresylic acid is used as a group II solvent, it willbe noted that the amount of a given soap is always much less than otherwise, and the percentage difierenceis much greater than the corresponding amount of rosin or cresylic acid added. These materials from this sub-group B of I 1 group II may be the only common solvent from said group II or may be a second group II common solvent, such as beingin addition to one of 1 I sub-groupA as will be apparent from inspection product is for dehydration following. preparation of the I soaps where water solutions areemployed in their water to yield a transparent emulsion which possesses unusual wetting ability in that itwill spread readily over various surfaces. For this reason the emulsions make desirable cutting oils as in the machining of steel such as threading .of the table, Asalso shown by the table, the soap content is at the'minimum (which is-an optimum 1 I condition) only when all three types of common solvent are used, 1. e. a water-soluble commonsoll I.

vent, an oil-soluble common solvent .ofsub-* I group A, and an oil-soluble common solvent of sub-group B. The proportion of'water indicated is of no particular consequence-its presence being usually a convenience which avoids the necessity production. The soap contents appear to be the optimum soap requirements for the respective compositions to obtain maximum transparency in the eventual water emulsion produced therefrom.

Soluble ozl compositions yielding transparent emulsions 1. Potassium naphthonatc l'rom Heavy gas oil Light lube oil 3. Common solvents Group I.-Woter-solublc Ethylene glycol Diothylone glycol 5 5 5 5 5 5 5 5 5 Group II.Oil soluble- Sub-group A Pine oil Alpha terpineol 5 alcohol Octyl Sub-group B-- Rosin proportions of water, are useful for dyeing,

oranges, the emulsions being good dye carriers. These transparent emulsions are superior to the ordinarily milky types of emulsions, and their superiority appears to be due principally to the superior wetting action mentioned. In the dyeing of oranges, for example, the dye is dissolved in the soluble oil before it is added to the water and the oranges then dipped in or passed through the emulsion.

The physical characteristics of the soluble oils In employing naphthenates produced from various oils as herein indicated and as represented in the accompanying table, it will be noted that, in general, the optimum amount of soap increases as the viscosity of the oil from which the naphthenic acids are recovered decreases, and that, therefore, the greater is the soap content and the lower the oil content as the molecular weight of the acids decreases. This requirement of greater optimum soap content as the molecular weight of the acids decreases suggests the theory that the higher the acid number of the naphthenic acids, the greater the amount of soap required, since the produced with the various naphthenates and lighter acids have the higher acid numbers. In

general, where greater proportions of soap are .soap content for the product of column 6 is con.-

siderably smaller than that of column by reason of the additional use of rosin, and the optimum soap content of column 7 is still smaller by reason of the additional use of cresylic acid. Conversely, referring to column 10, the optimum soap content may be increased by reason of employing small quantities of common solvent. At the same time the acid numbers of the materials of column were somewhat higher. Referring again to column 10, it will be noted that the rosin content of 3% is much less effective in the absence of a sub-group A solvent than the rosin content of 5% with a sub-V-group A solvent. It has been discovered that each additional percent of rosin above 2% has an increasingly greater eifect on soap reduction up to the optimum of 5%, above which the soap requirement tends to increase again. Thus, it has been discovered that the optimum rosin content is between about 4% and 5% calculated on a substantially water-free basis. These examples are also basis for the statement that greater amounts of soap are required as the percentages of common solvents are decreased, as well as for the statement that greater amounts of soap are required as the molecular weight decreases and the acid number increases.

From the foregoing disclosures it will be noted that the combined amount of common solvents may vary from about 5% to about The total amount of common solvents could be increased to perhaps although in practice such a greater amount appears to have no substantial amount of added beneficial efiect. Similarly, generally speaking, the minimum amounts of naphthenates required to produce said transparent emulsions may vary from about 10% for soaps produced from the heavy molecular weight acids to as high as 65% or even 75% of soaps produced from low molecular weight acids of high acid number, these being calculated on a substantially water-free basis. As has been indicated, where the common solvent including rosin is reduced toward the lower limit of 5%, the soap content needs to be increased, and similarly, as the rosin or cresylic acid is reduced, the soap content needs to be increased, for any given naphthenic acid from which the soap is produced. As seen in the above table, the minimum soap content for any given naphthenate is attained only when the three types of common solvents are present, namely a water-soluble common solvent of group I, an oil-soluble common solvent of subgroup A of group II, and an oil-soluble common solvent of sub-group B of group II.

All of the compositions as herein disclosed and as represented in the above table are readily dispersible in water to yield transparent emulsions. These emulsions, as have been indicated, are useful in the metal working industries as cutting oils and the like, and also as carriers for dyes in the dyeing of citrus fruits and the like, and for kindred uses where soluble oils are employed.

It is to be understood that these disclosures are given as illustrative of the generic invention rather than as limiting thereof.

I claim:

1. An emulsifiable oil comprising light mineral lubricating oil, alkali metal naphthenate from light lubricating distillates in the order of 30% to 45% of the total composition, a primarily watersoluble common solvent in the form of about 5% of a high boiling glycol, and a primarily oilsoluble, water-insoluble common solvent from the class consisting of aliphatic alcohols, pine oil and alpha terpineol in amount between about 5% and about 10% of the composition, the common solvents and naphthenate being present in proportions to yield transparent emulsions in water.

2. A composition according to claim 1 wherein the naphthenate is potassium naphthenate.

3. A soluble oil comprising a refined mineral oil, at least about 30% of an alkali metal naphthenate, approximately 5% of an ethylene glycol as a common solvent, and between about 5% and about 10% of a principally oil-soluble common solvent of the class consisting of aliphatic alcohols, pine oil and terpineol.

4. A soluble oil comprising refined mineral oil, at least about 30% of alkali metal naphthenates in the order of 5% of an ethylene glycol as a common solvent, and in the order of 5% of a largely oil-soluble common solvent from the class consisting of rosin, other abietic acid-containing materials and cresylic acid, the common solvents and the naphthenate being in proportion with respect to one another and to the oil content to, insure transparent emulsions in water.

5. A composition according to claim 4 containing in the order of 5% of a third common solvent from'the class consisting of pine oil, alpha terpineol and octyl alcohol.

6. An emulsifiable oil comprising a refined mineral oil, alkali metal soaps of high molecular weight naphthenic acids'from petroleum fractions in the range of heavy lubricating oils in the order of 10% to 30%, an ethylene glycol as a common solvent, a largely oil soluble common solvent of the class consisting of abietic alcohols, pine oil and terpineol and a largely oil-soluble common solvent of the class consisting of rosin, other materials containing abietic acid and cresylic acid, each of the common solvents approximating from 5% to 10% of the composition, and the refined mineral oil being in the order of 55% to of the composition.

7. An emulsifiable oil comprising refined mineral oil, alkali metal soaps from naphthenic acids derived from petroleum fractions in the range of light lubricating oils in the order of 30% to 45% of the composition, ethylene glycol as a common solvent, and a largely oil-soluble common solvent of the class consisting of aliphatic alcohols, pine oil and terpineol, each of the common solvents being in the order of 5% to 10% of the composi- I tion, the refined mineral oil being in the order of 40% to 75% of the composition.

8. An emulsifiable oil comprising refined mineral oils, alkali metal naphthenates from naphthenic acids of relatively low molecular weight derived from petroleum fractions in the range of gas oils and lighter fractions in the order of 40% to 65%, an ethylene glycol as a common solvent, and a largely oil-soluble common solvent, the common solvents being present in the order of 5% to 15% of the composition and the mineral oil being present in the order of 20% to 40% of the composition.

.water-soluble-common solvent in the form of a high boiling glycol, and a chiefly oil-soluble, water-insoluble common solvent of the class consisting of aliphatic alcohols, pine oil and terpineol, and a chiefly oil-soluble common solvent of the class consisting of abietic acid materials and cresylic acid, the common solvents being present in the oil composition in an amount between about 5% and 15%, the resultant water emulsion being transparent.

10. An emulsion comprising water and a soluble oil comprising a refined mineral oil, at least about 10% of potassium naphthenate, an ethylene glycol as a common solvent approximating 5% of the soluble oil composition and a chiefly oil-soluble common solvent approximating 5% to 10% of the soluble oil of the class consisting of aliphatic alcohols, pine oil and terpineol, and a second chiefly oil-soluble common solvent of the class consisting of abietic acid materials and cresylic acid, the emulsion being transparent.

11. An emulsifiable oil according containing an oil-soluble fruit dye.

12. An emulsifiable oil according to claim 1 containing an oil-soluble fruit dye.

13. An emulsion according to claim 10 containing an oil-soluble fruit dye.

14. An oil according to claim 10 containing. an oil-soluble common solvent of the class consisting of aliphatic alcohols, pine oil and terpineo l, and a second oil-soluble common solvent of the class consisting of abietic acid and cresylic acid.

15. An emulsifiable oil adapted to yield transparent emulsions in water comprising a refined mineral oil fraction, at least about 20% of an alkali metal naphthenate derived from light lubri cating oil distillates, a high-boiling glycol in the to claim 4' order of about 5%, a primarily oil-soluble waterinsoluble common solvent in the order of about 5% to about 10% from the class consisting of aliphatic alcohols, pine'oil and terpineol, and a 5 second primarily oil-soluble common solvent in the order of about 5% from the class consisting of abietic acid materials and cresylic acid.

16. An oil according to claim 15 wherein the naphthenate is potassium naphthenate.

17. An oil according to claim 3 where the naphthenate is potassium naphthenate.

18. An emulsifiable oil comprising a refined mineral lubricating oil, alkali metal naphthenate, \a primarily water-soluble common solvent in the l5 form of a high-boiling glycol, and a primarily oil-soluble, water-insoluble common solvent of the class consisting of high-boiling aliphatic alcohols, pine oil, alpha terpineol, and another oil soluble common solvent of the group consisting of rosin and other materials containing abietic acid, and

cresylic acid, common solvents and naphthenate being present in the oil to yield transparent emulsions in water; and wherein the naphthenate when-derived from heavy gas-oil is present in the order of 48% to 75%, and the naphthenate when derived from heavy lubricating oil is present in the order of to 30%, and the naphthenate when derived from light lubricating oil is present in the order of 30% to 37% when about 5% of 30 the glycol is used with from 5% to of only one of said oi1soluble common solvents, and said light lubricating oil naphthenate is present in the order of to 23% when about 5% of glycol is employed with about 5% of one of an oil-soluble sub-group consisting of said rosin, abietic acid and cresylic acid and also with about 5% to 10% of one of an oil-soluble sub-group consisting of the said aliphatic alcohols, ping oil, and alpha terpineol.

WILLIAM E. BRADLEY. 

